Family-based association study of interleukin 6 (IL6) and its receptor (IL6R) functional polymorphisms in schizophrenia in the Polish population.

Abstract

Schizophrenia is a heterogeneous disorder and its etiology remains incompletely elucidated. Among possible causes, immunological factors have been implicated in its pathogenesis and course. The inflammatory system may trigger or modulate the course of schizophrenia through complex mechanisms influencing neurodevelopment, neuroplasticity and neurotransmission. Recent studies indicate a role of excessive interleukin-6 (IL6) signaling in the pathogenesis of schizophrenia. Findings regarding changes in the circulating levels of soluble interleukin-6 receptor (sIL6R) in schizophrenia have been equivocal. The study was performed on a group of 147 trio (patients diagnosed with schizophrenia and their healthy parents). Polymorphisms of IL6 (rs1800795, rs1800797) and IL6R (rs4537545, rs4845617, rs2228145) genes were genotyped with the use of TaqMan SNP Genotyping Assays. No association of the polymorphisms from IL6 and IL6R genes with schizophrenia was found. We also investigated haplotypes in IL6 gene (consisting of rs1800795 and rs1800797) and in IL6R gene (consisting of rs4537545, rs2228145). We also found no preference in transmission of any haplotype. Our results do not support the theory that polymorphisms of IL6 and IL6R genes are involved in the pathogenesis of schizophrenia. It seems advisable to carry out further examinations of the role of these polymorphisms in schizophrenia by means of TDT method and classical (case-control) association method.